ICD-10 M23
Non-Billable HeaderInternal derangement of knee
About ICD-10-CM M23
ICD-10-CM code M23 represents Internal derangement of knee. This is a non-billable header code in the Musculoskeletal and Connective Tissue chapter (block M23). The 2026 edition of ICD-10-CM M23 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Type 1 Excludes
Pure excludes, these codes can never be coded together with M23. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- ankylosis (M24.66)
- deformity of knee (M21.-)
- osteochondritis dissecans (M93.2)
Type 2 Excludes
Not included here, the excluded code is not part of M23, but a patient may have both conditions at the same time. Both codes may be coded together when applicable.
- current injury - see injury of knee and lower leg (S80-S89)
- recurrent dislocation or subluxation of joints (M24.4)
- recurrent dislocation or subluxation of patella (M22.0-M22.1)
Medicare LCD Coverage for M23
Local Coverage Determinations (LCDs) from CMS MACs that list M23 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing M23.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but M23 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with M23
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To M23
Other codes in section M20-M25 (Other joint disorders).
ICD-10 M23, Billing FAQ
Is ICD-10 code M23 billable? +
No, M23 is a non-billable header code. Use a more specific child code from block M23 when submitting claims.
What codes are Type 1 Excludes for M23? +
Type 1 Excludes (never code together with M23): ankylosis (M24.66); deformity of knee (M21.-); osteochondritis dissecans (M93.2)
What codes are Type 2 Excludes for M23? +
Type 2 Excludes (may be coded together when both conditions exist): current injury - see injury of knee and lower leg (S80-S89); recurrent dislocation or subluxation of joints (M24.4); recurrent dislocation or subluxation of patella (M22.0-M22.1)
Get the full PayerReady toolkit
Free access to CPT/ICD-10 lookup, denial appeals, fee comparator, and claim auditing with credentialing enrollment.
Start free →Run this code through our claim audit tool
Check NCCI bundling, MUE limits, and modifier logic before submission.
Try the auditor →Did this page help?
Quick signal so we know what to improve.
If you want a code reference page that doesn't exist yet, email coding@payerready.com.
Tell us what's missing or wrong: coding@payerready.com. We respond within 5 business days.
Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
Powered by 11K CPT · 98K ICD-10 · 860K MPFS rates · 4.5M NCCI edits · 9.5M NPIs. Our data methodology · About our coding team